The mouse macrophage Man/GlcNAc receptor serves many important immune functions. To understand the function and biochemical properties of this receptor, the following is proposed: (1) examination of the effects of immune complexes on Man/GlcNAc receptor function. Immobilized complexes such as DNP-anti DNP antibody or monoclonal anti-sheep serythrocyte-sheep erythrocyte ghosts will be used to modulate macrophage receptors of the phagocytosis of zymosan studied. Soluble complexes such as TNP-bovine serum albumin-anti-TNP antibody will be used to compete for Man/GLcNAc receptor-mediated horseradish peroxidase uptake; (2) derivation of Man/GlcNAc receptor-positive cell lines by transfecting bone marrow cells and alveolar and peritoneal macrophages with SV4O Ori-DNA; (3) identification and characterization of the Man/GlcNAc receptor by (a) immunoprecipitation and polyacrylamide gel electrophoretic analysis of macrophage surface proteins by an antimouse macrophage heteroantiserum extensively absorbed with Man/GlcNAc receptor-negative cell line; (b) development of monoclonal antibodies by rat X rat fusions and screening for anti-mouse receptor activity. [125I]-anti-rat second antibody-labeling of hybridoma supernatant-treated macrophages, as well as blockage of macrophage uptake of zymosan and horseradish peroxidase by hybridoma supernatants will be used for screening; (c) affinity-labeling of the Man/GlcNAc receptor by labeled conjugates of mannose or horseradish peroxidase oligosaccharides; and (4) examination of the functional role of the Man/GlcNAc receptor in indicating macrophage secretion of H202 and macrophage-binding to tumor cells. Oligosaccharides conjugated to polymers, beads or substrates will be used for the triggering of macrophage secretion while cellular glycoprotein, glycolipids and oligosaccharides released from the glycoconjugates will be used in solution or coupled to substrates to compete for binding of tumor cells to macrophages. These experiments will further clarify the role of carbohydrates in immune functions and the role of the Man/GlcNAc receptor in macrophage functions. (MB)